It is estimated that approximately one million adults in the United States have language impairments as a result of stroke or head trauma. Such deficits, aphasias, frequently impair all modalities of language use - speaking, comprehending, reading, and writing - thus severely compromising an individual's capacity to interact with family members and in the community. The primary goal of rehabilitation programs is to promote the patient's ability to use residual language skills to cope with daily life situations. Despite the priority given to verbal communication abilities in intervention programs, there has yet to be developed a reliable and valid test to assess these abilities in language impaired populations. The primary goal of the proposed research project is to standardize such a test. This requires language testing of aphasics in the acute stage, having just become aphasic, in the recovery period during which changes in language behavior are observed, and in the chronic stage, six or more months post-onset. The study of acute and recovering patients provides a context for detailed analyses of the evolution of functional language abilities following onset of aphasia, the role of neurological, aphasiological, and biographical variables as prognostic factors in recovery, and the role intervention programs designed to promote functional language abilities. The result of this research will be directly applicable to the assessment of aphasics and to the design of rehabilitation programs in light of the prognostic factors identified in the study of evolution of communicative abilities following onset of aphasia.